The Taleban have said they will kill the hostages if the body of their former commander is not handed over.

The BBC's Charles Haviland in Kabul says the Taleban have not guaranteed to free any of the hostages even if the body is collected.

Mullah Dadullah, who lost a leg fighting Soviet forces, is alleged to have orchestrated numerous Taleban suicide attacks and beheadings.

He was killed in a US-led military operation in Helmand province and buried in an undisclosed location.

"We hope that they will release our workers safe and secure," Mr Fahim said. "Now it is up to local authorities in Kandahar... to hand over the body [to the family]," he said.

Kidnap controversy

Correspondents say it is not immediately clear when the swap will be made.

In March there was outrage in Afghanistan and international condemnation of President Karzai after his government made a deal made with the Taleban to secure the release of a kidnapped Italian journalist, Daniele Mastrogiacomo.

The government's critics at home said it was too easily bowing to enemy demands, and that it was putting the plight of a foreigner above that of Afghans who were kidnapped along with the journalist.

In April, an Afghan journalist kidnapped with the Italian was killed by the Taleban. Their driver was beheaded in March.

The US and UK said that the release of five militants in exchange for Mr Mastrogiacomo endangered Nato troops and encouraged kidnappings.